This invention relates generally to a novel building block, and more particularly to a modular building block that is interlocked with similar blocks to form high strength structures in a wide variety of different configurations such as retaining walls and various types of support structures.
Building blocks are used in a wide variety of applications such as in retaining walls for securing earth embankments and in support structures for holding various items above ground. The blocks are typically superimposed on top of each other in multiple layers. To reduce the time and cost of constructing walls and alternative support structures, it is desirable to assemble the blocks without having to use mortar, auxiliary pins, or additional attachment apparatus. However, a wall assembled by simply laying blocks on top of each other in multiple layers, does not provide sufficient inter-structural support for many applications.
Various interlocking blocks have been used to increase the overall structural integrity of walls. For example, U.S. Pat. No. 3,936,989 to Hancock describes blocks that have longitudinally extending ribs and grooves that interlock with the grooves and ribs of vertically adjacent blocks of the same shape. U.S. Pat. No. 4,124,961 to Habegger describes building blocks having longitudinally extending triangular ridges and a complementary depression that engage with similar bricks to restrain brick movement in a transverse direction.
The blocks described in Hancock and Habegger, however, can only be interlocked in one direction. Therefore, special separate end pieces must be used in order to change wall directions. For example, if a wall changes directions by 90 degrees, special corner blocks must be manufactured that engage with adjacent blocks oriented at 90 degree angles. Special end blocks increase the overall cost of building the wall and can also reduce structural integrity. Using special corner blocks for each directional change also limit the number of wall configurations that can be built.
U.S. Pat. No. 5,154,032 to Ritter describes a block that engages at various angles with blocks of similar design. Each block has a rectangular main portion that is connected at one end to a bulbous portion. The bulbous portion is received into a concave socket region of a second block. The bulbous portion and the concave socket, however, do not provide a positive interlock between overlapping block layers. Thus, a wall fabricated from this type of block is not as structurally sound as alternative interlocking block systems.
The opposite lateral ends of the block in Ritter are also not symmetric. Therefore, one block cannot be used for making multiple end pieces. For example, blocks in vertically adjacent rows are typically offset to increase overall wall strength. Because each row is skewed, half-bricks must be used at the end of the wall in every other row to provide a vertically straight wall edge. If each block had symmetric ends, one block could be used to make two half-blocks. However, each end of the block described in Ritter has a different configuration. Therefore, only one half-block can be made from each block. This further increases the overall cost of constructing a wall.
In general, building blocks are heavy and hard to grab onto making installation difficult. Because building blocks are hard to lift and carry, they are often dropped during transport, either damaging the block itself or damaging the surface that the block is dropped on.
Accordingly, a need remains for an easy to carry building block that is easily assembled into a wide variety of different interlocking structural configurations.